Nominatim/lib-sql/functions/postcode_triggers.sql

-- SPDX-License-Identifier: GPL-2.0-only
--
-- This file is part of Nominatim. (https://nominatim.org)
--
-- Copyright (C) 2025 by the Nominatim developer community.
-- For a full list of authors see the git log.

-- Trigger functions for location_postcodes table.


-- Trigger for updates of location_postcode
--
-- Computes the parent object the postcode most likely refers to.
-- This will be the place that determines the address displayed when
-- searching for this postcode.
CREATE OR REPLACE FUNCTION postcodes_update()
  RETURNS TRIGGER
  AS $$
DECLARE
  partition SMALLINT;
  location RECORD;
BEGIN
    IF NEW.indexed_status != 0 OR OLD.indexed_status = 0 THEN
        RETURN NEW;
    END IF;

    NEW.indexed_date = now();

    partition := get_partition(NEW.country_code);

    NEW.parent_place_id = 0;
    FOR location IN
      SELECT place_id
        FROM getNearFeatures(partition, NEW.centroid, NEW.centroid, NEW.rank_search)
        WHERE NOT isguess ORDER BY rank_address DESC, distance asc LIMIT 1
    LOOP
        NEW.parent_place_id = location.place_id;
    END LOOP;

    RETURN NEW;
END;
$$
LANGUAGE plpgsql;


CREATE OR REPLACE FUNCTION postcodes_delete()
  RETURNS TRIGGER
  AS $$
BEGIN
{% if not disable_diff_updates %}
  UPDATE placex p SET indexed_status = 2
   WHERE p.postcode = OLD.postcode AND ST_Intersects(OLD.geometry, p.geometry)
         AND indexed_status = 0;
{% endif %}

  RETURN OLD;
END;
$$
LANGUAGE plpgsql;


CREATE OR REPLACE FUNCTION postcodes_insert()
  RETURNS TRIGGER
  AS $$
DECLARE
  existing RECORD;
BEGIN
  IF NEW.osm_id is not NULL THEN
    -- postcode area, remove existing from same OSM object
    SELECT * INTO existing FROM location_postcodes p
      WHERE p.osm_id = NEW.osm_id;

    IF existing.place_id is not NULL THEN
      IF existing.postcode != NEW.postcode or existing.country_code != NEW.country_code THEN
        DELETE FROM location_postcodes p WHERE p.osm_id = NEW.osm_id;
        existing := NULL;
      END IF;
    END IF;
  END IF;

  IF existing is NULL THEN
    SELECT * INTO existing FROM location_postcodes p
      WHERE p.country_code = NEW.country_code AND p.postcode = NEW.postcode;

    IF existing.postcode is NULL THEN
{% if not disable_diff_updates %}
      UPDATE placex p SET indexed_status = 2
       WHERE ST_Intersects(NEW.geometry, p.geometry)
             AND indexed_status = 0
             AND p.rank_address >= 22 AND not p.address ? 'postcode';
{% endif %}

      -- new entry, just insert
      NEW.indexed_status := 1;
      NEW.place_id := nextval('seq_place');
      RETURN NEW;
    END IF;
  END IF;

  -- update: only when there are changes
  IF coalesce(NEW.osm_id, -1) != coalesce(existing.osm_id, -1)
     OR (NEW.osm_id is not null AND NEW.geometry::text != existing.geometry::text)
     OR (NEW.osm_id is null
         AND (abs(ST_X(existing.centroid) - ST_X(NEW.centroid)) > 0.0000001
              OR abs(ST_Y(existing.centroid) - ST_Y(NEW.centroid)) > 0.0000001))
  THEN
{% if not disable_diff_updates %}
    UPDATE placex p SET indexed_status = 2
      WHERE ST_Intersects(ST_Difference(NEW.geometry, existing.geometry), p.geometry)
            AND indexed_status = 0
            AND p.rank_address >= 22 AND not p.address ? 'postcode';

    UPDATE placex p SET indexed_status = 2
      WHERE ST_Intersects(ST_Difference(existing.geometry, NEW.geometry), p.geometry)
            AND indexed_status = 0
            AND p.postcode = OLD.postcode;
{% endif %}

    UPDATE location_postcodes p
      SET osm_id = NEW.osm_id,
          indexed_status = 2,
          centroid = NEW.centroid,
          geometry = NEW.geometry
      WHERE p.country_code = NEW.country_code AND p.postcode = NEW.postcode;
  END IF;

  RETURN NULL;
END;
$$
LANGUAGE plpgsql;